Algae's Impact: Water Pollution And Environmental Concerns

Algal blooms are the explosive growth of algae in water bodies, which can be harmful to both aquatic life and human health. They are caused by a combination of factors, including nutrient pollution, rising temperatures, and climate change. Excess nutrients, such as nitrogen and phosphorus, act as fertilisers, causing algae to grow faster than ecosystems can handle. This leads to a thick layer of algae that blocks sunlight and consumes oxygen, resulting in dead zones where aquatic life cannot survive. Additionally, certain types of algae produce toxins that contaminate drinking water and harm humans and animals. The increase in harmful algal blooms is a growing environmental concern, impacting freshwater ecosystems and human communities worldwide.

Algae can cause dead zones

The decomposition of algae also contributes to oxygen depletion in water. When algae die, they sink to the bottom of the water, and bacteria break them down, consuming oxygen in the process. This further reduces the oxygen available for aquatic life, exacerbating the deadly effects of HABs.

The Gulf of Mexico is home to the largest dead zone in the United States, covering an area of about 6,500 square miles. This dead zone occurs annually during the summer months due to nutrient pollution from the Mississippi River Basin. The basin drains 31 states, encompassing a vast area of farmland that contributes to nutrient runoff, fuelling the growth of HABs.

The frequency and duration of dead zones have increased since the 1970s, with over 166 dead zones identified across the nation. These dead zones have detrimental effects on aquatic ecosystems, impacting bays, lakes, and coastal waters. The Chesapeake Bay, for instance, is affected by dead zones, posing a threat to the health of aquatic life in the region.

The formation of dead zones is influenced by various factors, including slow water circulation, high water temperatures, increased nutrients from runoff, and weather events such as hurricanes, floods, and droughts. These factors create favourable conditions for the growth of HABs, which can have devastating consequences for marine environments and the organisms that inhabit them.

Algae can be toxic to humans

Consuming contaminated water or eating seafood containing algal toxins can result in gastroenteritis, causing vomiting, diarrhoea, fevers, and headaches. These toxins may also impact the liver or nervous system. In more severe cases, harmful algal blooms (HABs) have been linked to neurotoxin poisoning, with symptoms including seizures, disorientation, and loss of muscle control.

The growth of HABs is fuelled by nutrient pollution, particularly excess nitrogen and phosphorus, which can come from sources such as farming fertilisers and sewage. HABs can occur in freshwater sources, such as lakes and rivers, as well as in coastal waters. They can be identified by discoloured water, often a green water colour, and the presence of foam, scum, mats, or paint-like substances on the water surface.

It is important to note that not all algae produce toxins, and boiling affected water does not remove toxins. To stay safe, it is recommended to avoid direct contact with algae-affected water, follow local advisories, and seek medical advice if you experience any symptoms after potential exposure.

Algae can be caused by nutrient pollution

Nitrogen and phosphorus are natural parts of aquatic ecosystems and support the growth of algae and aquatic plants. However, when too much nitrogen and phosphorus enter the environment, usually from a wide range of human activities, they can pollute the air and water. Nutrient pollution has impacted many streams, rivers, lakes, bays, and coastal waters, resulting in serious environmental and human health issues.

Excess nitrogen in the air can impair our ability to breathe, limit visibility, and alter plant growth. When excess nitrogen returns to Earth from the atmosphere, it can harm forests, soils, and waterways. Similarly, excess phosphorus can also have negative impacts on the environment and human health.

The dramatic surge in nutrient flow from industrial, urban, and agricultural activities accelerates the eutrophication of lakes, streams, and coastal waters. Crop production involves chemical fertilisers or animal manure containing nitrogen and phosphorus. Fertilised soils and livestock operations release many nutrients into the air and waterways. Municipal sewer and septic systems often fail to remove nitrogen and phosphorus from urban waste, leading to increased nitrate and phosphorus pollution in waterways.

Climate change and human activities, such as industrial operations, transportation, and agriculture, also contribute to nutrient pollution and the growth and spread of algae. The natural biogeochemical cycles of nitrogen and phosphorus can be disrupted by the increased effects of climate change. As a result, harmful algal species are quickly adapting to the growing nutrient loads.

To combat eutrophication and reduce the impact of nutrient pollution on algae growth, comprehensive control and preventative measures are necessary. Governments, businesses, and individuals must take urgent actions to reduce nutrient pollution and restore damaged ecosystems. Controlling nutrient flow, especially from point sources such as mines and factories, is crucial. Additionally, upgrading land use management, landscape management, and water management practices can help reduce nutrient runoff and losses through leaching.

Algal blooms can be caused by rising temperatures

Algal blooms are runaway growths of algae that can devastate marine ecosystems and harm human health. They are caused by a sudden increase in nutrients such as nitrogen and phosphorus, which are often found in agricultural fertilisers. When algae receive excess nutrients, they grow at an explosive rate, forming blooms that can turn toxic. These blooms consume oxygen and block sunlight from underwater plants, creating "dead zones" where aquatic life cannot survive.

Rising temperatures have been identified as a key factor contributing to the increasing frequency and intensity of algal blooms. Warmer waters provide favourable conditions for certain species of algae to thrive, such as cyanobacteria, which are commonly found in harmful algal blooms (HABs). As temperatures rise, these algae grow faster and outcompete other species.

The impact of rising temperatures on algal blooms was evident in a study examining North America's Lake Erie in 2011, one of the worst algal blooms in decades. Warmer ocean temperatures were found to intensify and prolong toxic outbreaks. This trend was further supported by research on the North Atlantic and North Pacific oceans, which revealed that rising temperatures increased the potential growth rates and lengthened the bloom seasons for harmful algae species.

The combination of rising temperatures and increased nutrient pollution exacerbates the problem. As farming fertilisers and sewage pollution enter warming waterways, the risk of turning drinking water toxic increases. This has already had significant impacts on human populations, with HABs causing rashes, fevers, and even liver and kidney damage.

The effects of climate change, including rising temperatures, are expected to make algal blooms more severe and frequent. Warmer water temperatures create ideal conditions for HAB-forming cyanobacteria, which grow faster and can migrate up and down water columns more effectively than other algae. Additionally, higher carbon dioxide levels in the air and water contribute to the rapid growth of algae, particularly cyanoHABs.

Algal blooms can impact aquatic ecosystems

Algal blooms can have a detrimental impact on aquatic ecosystems. They can reduce the ability of fish and other aquatic life to find food and can cause entire populations to leave an area or even die.

Harmful algal blooms (HABs) can produce toxins that are detrimental to fish and other animals. These toxins can move up the food chain, impacting larger animals like sea lions, turtles, dolphins, birds, and manatees. They can also cause fish kills, as well as mammal, bird, and human illness.

Even if algal blooms are not toxic, they can still negatively impact aquatic life by blocking out sunlight and clogging fish gills. They can also create "dead zones" where there is so little oxygen that aquatic life cannot survive. This occurs when the overgrowth of algae consumes oxygen and blocks sunlight from underwater plants. When the algae die, they further decrease the oxygen levels in the water as they decompose.

The frequency and duration of dead zones have increased since they were first noticed in the 1970s. Over 166 dead zones have been documented in the United States, affecting water bodies like the Chesapeake Bay and the Gulf of Mexico.

In addition to the direct impacts on aquatic life, algal blooms can also have economic impacts. They can reduce tourism, recreation, commercial fishing, and property values, as well as increase water quality monitoring, management, and treatment costs. For example, a persistent algal bloom in an Ohio lake from 2009 to 2010 caused an estimated loss of $47 million in local tourism revenue.

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